Rechargeable battery



Patented Sept. 9, 1952 RECHARGEABLE .narrow Michel N. Yardeny, New York,-N, Y.,nowby judicial change oftname MichelfN. Yardney, `assigner to, Yardney International Corp., New York, N, Y a corporation New York 1 Application Aprire, 195o, scritti 10.153330 1 e i e a The present invention relates to improvements in rechargeable batteries of thesilver and zinc type, more particularly of the type disclosed in co-pending application Ser. No. 131,320, filed December 6, 1949, now Patent No. 2,601,133, issued June 17, 1952.

'An important object of the present invention is toprovide, in a battery of this type, means for reducing the internal resistance thereof. i

Another object of this invention is to provide a battery of reduced dimensions (and weight) fora given storage capacity, or of increased storage capacity for a given size.

A further object of the invention is to provide means forV increasing the number of successive charging and discharging cycles to which a bat-A ter-y of'this description may be subjected.

In prior disclosures, such as co-pending application Ser. No. 738,702, filed by H. Andr on April` 1,219.47, now. Patent No; 2,594,709, issued Aprll29,.l952, it hasbeen shown that a cell -re chargeable a large rinu'mber of l times maybe formed by .juxtaposing 'in a container a positive silver electrode and Va negative 'zinc electrode separated byone ormore layers of cellophane and so'dimensioning the container that the cel--A lophane, when caused to swell by the `additicm of alkaline electrolyte, will not nd room'tosatisfy completely its tendency to expand, `thereby' placing the assembly under compressionsuchfasl to limit the size of the pores of the cellophane; as a result, migration of particles Vfrom one electrode tothe other will be prevented and internalshort circuits, so destructive of prior batteries of this general type, will be avoided.

It has been noted, however, that batteries of the type set forth were subject to relatively early deterioration believed to be due to interaction between the cellophane and the positive electrode which in the charged condition Vofthe Vbattery consists, at least to a large degree, of silver DB1.- oxide, a compound known to have powerful oxidialing effects. a i

',Ihe invention avoids the above dSadvantage by nreplacing at least part of theV cellophane wrapper surrounding the positive electrode, i. e. the part closest to the silver, with a material substantiallyfree fromreagents capable Aofreacting with the silver electrode.`

`This may be accomplished, in]accordanceI with a feature' of the present invention, by interposing one or' more layers of anelectrolyte-perme-i able material,` which `should be'` free fromglycernandfermeldehyde, between the 'silver and. the cellophane proper. Asutable materialof 7 (Bacillus.V

(cricca-'611.

this description i is natural cellulosic paper,- that is to say,paper whosefcellulosic base is leftin its naturally absorbent `stateby omitting the cus-- tomary operations of glazing, sizing and the like.

` Paper ofthis character is commercially available underV the -trade name Alden Ordinaryblottingpaper also fits this description;

The useof an electrolyte-permeable spacer of the character descrbed,in combination with areduced number of semi-permeable cellophane layers, has an additional advantage besides inhibitingany untoward rise in the internal resistance of the cell due to the causes set forth: Since the coefficient of expansion of the natural cellulosc paper, when absorbing electrolyte, is somewhat less than that of cellophane, e. g. has thenumerical value of approximately 2 (i. e. the paper tends to swell to double its original thickness) as eompared with a coefficient of about "3 l fo'rcellophane; the dimensions of the container or'casingfenclosing the assembly may be reduced without resulting in a compression of the diaphragm exceeding that at Awhich the permeability of Vthecellophanefisan optimum.

1 have also discovered va method of further re'- ducinggthe internal resistance of the` cell by amalgame/ting the zinc, of the negative electrode. Such`amalgamationehas` already been proposed invthegcase of zincfoils,ibut has notheretofore been usadas far as I am aware, in a cell whose.f

negative electrode `consists of powdered zinc (or proved highly satisfactory. Ratios as high as.,

10% HgO, per weight of zinc oxide, have been found to besuitable. This method and an electwill?Y ,SQ `constitutedare claimed in `a divisional application.` Ser. No. 288,556, filed. May 171952.r

Referenceis now made to the accompanying drawing for a better understanding 0f"` the inf, vention. In the drawing: i w

\ `Fig1l is a plan view of alpositive electrode element41 a rst stage of formation thereof; y

Fig. 2 isaffront elevation of the same *elementi in, an advanced stage of formation;

Fig.j3 isaside elevation of `this elementin a further stage of formation;`

LFi'g, f1 is a' cross `secti`on,.on a `larger scale,`

through a battery `casing and a complete elec#- trode assembly, according to the present improvement, inserted therein; and

Fig. 5 is a cross sectional view similar to Fig. 4, showing a modification.

Referring flrst to Fig. 4 for a description of the various elements of my improved battery and the relative arrangement thereof, there is shown a rigid casing I containing a negative electrode I I flanked by two positive electrodes I2a, I2b. The negative electrode is separated from each of the two positive electrodes by three .diaphragmsV including a negative Wrapper I3 and'positive wrappers I4a, I4b of relatively high permeability, i. e. of natural cellulosic paper asdei'ined above,

and an inter-electrode spacer I5 of relatively low permeability, i. e. of cellophane. The Wrappers I3, I4 are each shown as consisting only o f a single layer, whereas the spacer I5 comprises a number of layers formed by a process which will be described with reference to Figs. 1-3. A negative lead I6 projects fromthe electrodel II while positive leads Ila, IIb, merging with eachother, project from the two positive electrode portions I2a, |212, respectively. l

Fig. -lrshows a rectangular strip of cellophane I5 upon which there are disposed, in spaced-V apart relation, thev two positive electrode portions I2a, I2b each in its'wrapper of natural cellulosic paper (not shown in Fig. l). Horizontal and vertical dot-dash lines indicate where the strip I5 is subsequently folded about these electrode portions toeproduce the envelope shown in Fig. 2 from which project the leads I'Ia, IIb, these leads passing through holes I9a, I9b which are made in the strip I5 and through which pass the vertical lines of fold.

After the folding of the envelope I5 has been completed, another strip I5 of cellophane is wrapped aboutthe former as clearly shown in Fig.-3.v The two strips I 5, I5, together forming the diaphragm or spacer I5 and enclosing the Velectrode portions I2a, I2b with their wrappers Ida, Mb, are then bent into U-shape to form the'positive element shown in Fig. 4 which enfolds the negative element I I, I3. `It will be noted that infcontradisti'nction to prior arrangements, such as disclosed, for example, in co-pending applications Ser. Nos'. 66,291 and 98,433 by H. Andr, led December 20, 1948 and June 11, 1949, respectively, now VPatents Nos. 2,594,710 and 2,594,712, issued April 29, 1952, the bight or center portion of the lU contains no active electrode material, the latter being divided between the positive'electrode portions I2a and I 2b located in the two arms thereof. rather surprisingly, that the reduction in output due to the elimination of the active material from part of the positive element is trivial when compared with the resulting economies in si1ver,`

space and weight, so that a considerable increase in'specic output, per unit of weight or size, was achieved. If, furthermore, a cellophane substantially free from plasticizer is used, the greater brittleness of the Ylatter is of no consequence inasmuch as any cracking of the diaphragm I5,

due to bending of the assembly into U-shape; will occur at non-vital points only.

In this connection it may be mentionedthat the formation of the positive, or outer, electrode element in the manner described above has been found conducive. to a further reduction in the internal resistance of the cell, as compared with electrode assemblies wherein, as previously proposed, 4the U-shaped electrode has an inner wrapping similar. to the wrapping I5 surrounded It has been found,V

by an outer envelope of the character shown at I5. The reasons for this advantageous result are not entirely clear but are believed to reside, at least in part, in the better over-all contact between the cellophane and the body of the electrode which is obtainable by virtue of the present arrangement, entailing a'substantial velimination of undesirable air pocketsbetweenithe electrode body and the wrappings surrounding it.

It should be understood that the invention is not limited .to the specific embodiment shown and described; thus it is to be noted that the positions of jthe positive and negative electrodes in a: battery as described may be interchanged, so

`that fthe negative electrode is given U-shaped 'configuration and'enfolds the positive electrode, and that certain of the advantages enumerated through 3 in connection with corresponding electrodes I2a, I2b. Since, however, the.n positive electrode vpads of Fig. 5 are not folded into U-shape, only one electrode, such as I2a' or. I2b in Fig. 4, is included in each cellophane wrapper. Negative electrodes IIIa and IIIb are respectively interposed between positive electrodes II2a, II2b and II2b, II2c, negative leads IIIia, IIGb merging with each other, and positive leads I I1a, I I'Ib, I I'Ic likewise merging with each other. Each electrode is encased in a layer of natural cellulosic paper such as I I3a or I Ida, each posi'- tive layer being further provided with an outer layer of cellophane, such as ,I I5a, composed of a folded envelope and a wound wrapping similar to members I 5 and I5 of Fig. 3, the entire assembly being mounted Within a rigid casingIIII. The functions of thel various components are identical with those explained in connectionrwith.

thev corresponding elements illustrated in Fig. 4,

the aforementioned correspondence being indicatedxby similar reference numeralsprexedfby.

an initial hundreds digit.

What lI claim as novel, and desire-tol secure by.

Letters Patent, is: A a

l.y InV a battery, in combination, a casing, at least one positive electrode and at least one negative electrode in said casing, at least said posif, t1ve electrode containing a strong oxidizing agent;

inthe charged condition of the battery, and diaphragm means separating said electrodes, said diaphragm means including at least one iirst sheetof semi-permeable material andat leastv onesecond sheet of permeable material inter- 3.'. In a battery, the combination according to claim 1 wherein said first sheet consistsof cello- 1 phane.

In a battery, the combination according to n claim l wherein said second sheetissubstanfv tially free from glycerin. l

u 5. In a. battery, in combination, a casing, at

least one positive electrode and atleast onenegaat least -said Vpositive `electrode in said casing, tive electrode containing a strong oxidizing agent in the charged condition of the battery,'and dia-- phragm means separating said electrodes, said diaphragm means including at least one first sheet of cellophane and at least one second sheet of natural cellulosic paper interposed between said rst sheet and saidpositive electrode, thereby protecting said cellophane from oxidation by said agent.

6. In a battery, the combination according to claim 5 wherein said positive electrode contains silver.

7. In a battery, the combination according to claim 3 wherein said cellophane is` substantially free from formaldehyde.

MICHEL N. YARDENY.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 309,939 Faure Dec. 30, 1884 425,335 Marx Apr. 8, 1890 428,684 Mason May 27', 1890 440,173 MacDonald Nov. 11, 1890 1,955,115 Drum Apr. 17, 1934 2,317,711 Andre Apr. 27, 1943 

1. IN A BATTERY, IN COMBINATION, A CASING, AT LEAST ONE POSITIVE ELECTRODE AND AT LEAST ONE NEGATIVE ELECTRODE IN SAID CASING, AT LEAST SAID POSITIVE ELECTRODE CONTAINING A STRONG OXIDIZING AGENT IN THE CHARGED CONDITION OF THE BATTERY, AND DIAPHRAGM MEANS SEPARATING SAID ELECTRODES, SAID DIAPHRAGM MEANS INCLUDING AT LEAST ONE FIRST SHEET OF SEMI-PERMEABLE MATERIAL AND AT LEAST ONE SECOND SHEET OF PERMEABLE MATERIAL INTERPOSED BETWEEN SAID FIRST SHEET AND SAID POSITIVE ELECTRODE, THEREBY PROTECTING SAID SEMI-PERMEABLE MATERIAL FROM OXIDATION BY SAID AGENT. 